1 / 15

ASYMMETRY IN TEMPERATURE OF SOLAR POLES

Learn about the groundbreaking discovery of temperature asymmetry at the solar poles by the Ulysses robotic probe, revealing intriguing differences between the North and South poles of the Sun. Explore the findings and potential causes of this phenomenon.

pennb
Download Presentation

ASYMMETRY IN TEMPERATURE OF SOLAR POLES

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. ASYMMETRY IN TEMPERATURE OF SOLAR POLES SOLAR PHYSICS January 18th, 2013 Pilar Herrero Sinovas

  2. Introduction: How was the asymmmetry discovered?

  3. Ulysses:Trajectory • The ESA-NASA Ulysses robotic probe was launched in October 1990. • Jupiter would accelerate Ulysses out of the ecliptic plane to high latitudes.

  4. Ulysses:Overflying the Poles Three times overflew the solar poles: • 1994-1995 Solar minimum • 2000-2001 Solar maximum • 2007-2008 Solar minimum

  5. Ulysses: SWICS The Solar Wind Ion Composition Spectrometer (SWICS): - Temperatures - Mean speeds of solar-wind ions

  6. Ulysses: SWICS • First orbit: SWICS measured the ratio O7+/O6+ • Lower in the North Pole Continuity equation: n, u: densidad y velocidad R: Tasa de recombinación C: Tasa de ionización Lower T in North Pole!

  7. SWICS: Results • Average temperature of the Sun's polar wind is about one million degrees C. • But over North Pole the wind is about 44.000 degrees cooler than over South!

  8. Magnetic Field • The "cool spot" follows the north magnetic pole when the sun's poles flip.

  9. What are the causes? UNKNOWN! • But related asymmetries have been studied for Polar Coronal Holes (PCH): - Area - Magnetic Flux Density - Wind Speed - Expansion Factor

  10. What are the causes? • All data from first flight over the poles (minimum)

  11. Asymmetry in Area • 1996 large polar coronal holes extend to or below 50º • North larger than the South: N = 8% S = 7%

  12. Asymmetry in Area Different Areas! North Larger

  13. Asymmetry in magnetic flux densities North: Magnetic Flux Density Twice lower!

  14. Expansion Factor and Velocity Expansion factor: Compares the magnitude of the photospheric magnetic field at the footpoint of the tube with its magnitude at 2.5 solar radii. North: • Higher velocity: 15-20 km/s • Lower expansion factor: 5%

  15. Summary But no definitive answer exists!! North Pole: Lower: - Temperature - Magnetic Flux - Expansion Factor Higher: - Area - Velocity

More Related